Various devices and methods have been developed in the past for the treatment of surfaces such as floors, roadways and the like where the surface to be treated, if not planar, has segments which are generally so. While a carpeted floor surface is obviously practically planar, a roadway or any other exemplary surface may be considered planar for the purpose of the invention if it has an axis lateral to the path traversed by the object which is generally straight and if the radius of curvature of the path traversed by the object is very large compared to the size of the object. Examples of the latter circumstances include street sweepers and road graders, both of which treat the travelled surface.
It is known that the rate at which a given apparatus can treat or otherwise prepare a particular surface per unit of time will depend in significant part upon the initial condition of the surface. Other factors such as the skill of the operator may also affect the rate at which a surface may be treated. When treating such surfaces, it is often useful for the operator to be able to readily ascertain the coverage rate at which the apparatus is proceeding across the surface and this information, coupled with personal observations of the operator, will permit the apparatus to be moved across the surface at the maximum speed consistent with satisfactory treatment.
As an example, persons who operate machines for applying cleaning products to carpets are confronted with carpets having widely varying surface characteristics and/or imbedded soil. A short pile carpet which is only lightly soiled may be cleaned at a more rapid rate than might a heavily soiled, deep pile or shag carpet. Confronted with any of the foregoing situations, experience, experimentation and judgment will usually suggest to an operator the maximum coverage rate at which a particular carpet surface may be cleaned. The invention will be highly beneficial in maintaining that rate.
As another example, an operator of a road grading machine may undertake to prepare and treat road surfaces, one of which has only sparsely distributed, small projecting imperfections and a second road surface on which such imperfections are both frequent and sizeable. Therefore, satisfactory treatment of the second road surface can only result if the machine is moved thereacross at a substantially lower rate compared to the first road surface.
Since apparatus such as the described carpet cleaning and road treating machines are relatively expensive and since their operation requires a skilled operator who is appropriately compensated for such skills, it is important at least for cost-saving reasons to operate the apparatus so that it traverses and treats a surface area in the minimum time, consistent with acceptable results. Prior efforts in this regard have resulted in machines operated totally according to the judgment and skill of the operator, which may be less than fully satisfactory. One result of such operation is that the machine may be used at a rate which underutilizes its capability. Another possible result is that the machine is used at a treatment rate in excess of that required to properly treat the surface and poor or unacceptable treatment results.
An apparatus which determines and makes available to the machine operator the area of a surface traversed and treated by an object per unit of time would be an important advance in the art. This is so since once the optimum treatment rate for a particular surface is determined--by judgment, experimentation or otherwise--this rate may be used as the standard for the most rapid utilization of such machines, consistent with acceptable quality of treatment. It would therefore be responsive to a long-standing need for a practical, easily usable apparatus which can dramatically reduce costs relating to labor and machine utilization.